I'm sorry to read about Ziggy, he sounds like he was loved by one and all, especially by his human mum. You're right, talking about him is what she needs and the more people who can share Ziggy stories to show how he was loved, the better.
This touches a chord in me as Brogan went during a walk as well. As far as I knew he was perfectly fine at 4pm going out for our walk but by 6:30pm he was gone. It's not ever easy no matter how you lose them but in time I've come to appreciate that it was so fast for his sake.